This objective of this investigation is to compare different liposome formulations for the ability to deliver vaccine antigens to the dendritic cells of the epidermis and initiate an effective immune response to target antigens following transcutaneous immunization. The choice of lipids used in liposome preparation should enhance penetration of the protein antigens through the stratum corneum into the epidermis, where immunologically-responsive cells exist. The first phase of the investigation will focus on uptake through the skin using an in vitro porcine model. Delivery of fluorescently-labeled liposomes and antigenic proteins to dendritic cells in the epidermis will be visualized as well. The second phase will determine the immunologic response, both serum and mucosal, to transcutaneously applied liposome-encapsulated Protective Antigen of Bacillus anthracis in a murine model. The immunogenicity of encapsulated versus free soluble protein will be compared. Lastly, the ability of a transcutaneously applied liposomal vaccine to protect immunized mice against an anthrax challenge will be assessed. Results will provide an understanding of influence of the lipid composition of liposomes on transport of proteins administered through the skin and the immunologic response to a transcutaneous liposomal vaccine, which could offer a new technique for protection against a number of infectious diseases. [unreadable] [unreadable] [unreadable]